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Gene knockout study reveals that cytosolic ascorbate peroxidase 2(OsAPX2) plays a critical role in growth and reproduction in rice under drought, salt and cold stresses.

Zhang Z, Zhang Q, Wu J, Zheng X, Zheng S, Sun X, Qiu Q, Lu T - PLoS ONE (2013)

Bottom Line: Loss of function in OsAPX2 affected the growth and development of rice seedlings, resulting in semi-dwarf seedlings, yellow-green leaves, leaf lesion mimic and seed sterility.H2O2 and MDA levels were high in Osapx2 mutants but low in OsAPX2-OX transgenic lines relative to wild-type plants after stress treatments.Taken together, the cytosolic ascorbate peroxidase OsAPX2 plays an important role in rice growth and development by protecting the seedlings from abiotic stresses through scavenging reactive oxygen species.

View Article: PubMed Central - PubMed

Affiliation: Biotechnology Research Institute, Chinese Academy of Agricultural Sciences/National Key facility for Gene Resources And Genetic Improvement, Beijing, China.

ABSTRACT
Plant ascorbate peroxidases (APXs), enzymes catalyzing the dismutation of H2O2 into H2O and O2, play an important role in reactive oxygen species homeostasis in plants. The rice genome has eight OsAPXs, but their physiological functions remain to be determined. In this report, we studied the function of OsAPX2 gene using a T-DNA knockout mutant under the treatment of drought, salt and cold stresses. The Osapx2 knockout mutant was isolated by a genetic screening of a rice T-DNA insertion library under 20% PEG-2000 treatment. Loss of function in OsAPX2 affected the growth and development of rice seedlings, resulting in semi-dwarf seedlings, yellow-green leaves, leaf lesion mimic and seed sterility. OsAPX2 expression was developmental- and spatial-regulated, and was induced by drought, salt, and cold stresses. Osapx2 mutants had lower APX activity and were sensitive to abiotic stresses; overexpression of OsAPX2 increased APX activity and enhanced stress tolerance. H2O2 and MDA levels were high in Osapx2 mutants but low in OsAPX2-OX transgenic lines relative to wild-type plants after stress treatments. Taken together, the cytosolic ascorbate peroxidase OsAPX2 plays an important role in rice growth and development by protecting the seedlings from abiotic stresses through scavenging reactive oxygen species.

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Spikelet fertility after stress treatments in T2OsAPX2-OX transgenic plants and WT plants.OX1, OX2, OX3 and OX4 are independent OsAPX2-OX lines. A: drought treatment, B: salt treatment, C: cold treatment. Values represent the mean ± SD (N = 10).
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pone-0057472-g012: Spikelet fertility after stress treatments in T2OsAPX2-OX transgenic plants and WT plants.OX1, OX2, OX3 and OX4 are independent OsAPX2-OX lines. A: drought treatment, B: salt treatment, C: cold treatment. Values represent the mean ± SD (N = 10).

Mentions: Studies have shown that rice yields are affected by the abiotic stress at the booting stage [35]. In order to understand whether or not the OsAPX2 functions in improving rice yields through enhancing tolerance to abiotic stresses, we compared the spikelet fertility of both OsAPX2-OX and wild-type plants at the booting stage. The T2 transgenic OsAPX2-OX plants and wild-type plants were stressed under drought, salt and low temperature treatments at the booting stage, respectively. Four independent OsAPX2-OX lines (OX1, OX2, OX3 and OX4) were used for each treatment in our assays. As shown in Figure 12, OsAPX2-OX and wild-type plants had similar spikelet fertilities under normal condition, while significant differences were found between OsAPX2-OX transgenic lines and wild-type plants under stress treatments. For drought treatment, the spikelet fertilities were decreased by 75% in wild-type plants, but were decreased by 56%, 52%, 60% and 57% in OsAPX2-OX lines (OX1, OX2, OX3 and OX4, respectively; Figure 12). For salt treatment, the spikelet fertilities were decreased by 54% in wild-type plants, but only reduced by 38%, 33%, 39% and 37% in OsAPX2-OX lines (OX1, OX2, OX3 and OX4, respectively; Figure 12). For cold treatment, the spikelet fertilities were decreased by 76% in wild-type plants, but only were reduced by 66%, 59%, 64% and 67% in OsAPX2-OX lines (OX1, OX2, OX3 and OX4, respectively; Figure 12). Moreover, our experiments in drought shed obtained the same results, showing that OsAPX2-OX plants were more tolerant to drought stress than wild-type plants at the booting stage (Figure S1).


Gene knockout study reveals that cytosolic ascorbate peroxidase 2(OsAPX2) plays a critical role in growth and reproduction in rice under drought, salt and cold stresses.

Zhang Z, Zhang Q, Wu J, Zheng X, Zheng S, Sun X, Qiu Q, Lu T - PLoS ONE (2013)

Spikelet fertility after stress treatments in T2OsAPX2-OX transgenic plants and WT plants.OX1, OX2, OX3 and OX4 are independent OsAPX2-OX lines. A: drought treatment, B: salt treatment, C: cold treatment. Values represent the mean ± SD (N = 10).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3585366&req=5

pone-0057472-g012: Spikelet fertility after stress treatments in T2OsAPX2-OX transgenic plants and WT plants.OX1, OX2, OX3 and OX4 are independent OsAPX2-OX lines. A: drought treatment, B: salt treatment, C: cold treatment. Values represent the mean ± SD (N = 10).
Mentions: Studies have shown that rice yields are affected by the abiotic stress at the booting stage [35]. In order to understand whether or not the OsAPX2 functions in improving rice yields through enhancing tolerance to abiotic stresses, we compared the spikelet fertility of both OsAPX2-OX and wild-type plants at the booting stage. The T2 transgenic OsAPX2-OX plants and wild-type plants were stressed under drought, salt and low temperature treatments at the booting stage, respectively. Four independent OsAPX2-OX lines (OX1, OX2, OX3 and OX4) were used for each treatment in our assays. As shown in Figure 12, OsAPX2-OX and wild-type plants had similar spikelet fertilities under normal condition, while significant differences were found between OsAPX2-OX transgenic lines and wild-type plants under stress treatments. For drought treatment, the spikelet fertilities were decreased by 75% in wild-type plants, but were decreased by 56%, 52%, 60% and 57% in OsAPX2-OX lines (OX1, OX2, OX3 and OX4, respectively; Figure 12). For salt treatment, the spikelet fertilities were decreased by 54% in wild-type plants, but only reduced by 38%, 33%, 39% and 37% in OsAPX2-OX lines (OX1, OX2, OX3 and OX4, respectively; Figure 12). For cold treatment, the spikelet fertilities were decreased by 76% in wild-type plants, but only were reduced by 66%, 59%, 64% and 67% in OsAPX2-OX lines (OX1, OX2, OX3 and OX4, respectively; Figure 12). Moreover, our experiments in drought shed obtained the same results, showing that OsAPX2-OX plants were more tolerant to drought stress than wild-type plants at the booting stage (Figure S1).

Bottom Line: Loss of function in OsAPX2 affected the growth and development of rice seedlings, resulting in semi-dwarf seedlings, yellow-green leaves, leaf lesion mimic and seed sterility.H2O2 and MDA levels were high in Osapx2 mutants but low in OsAPX2-OX transgenic lines relative to wild-type plants after stress treatments.Taken together, the cytosolic ascorbate peroxidase OsAPX2 plays an important role in rice growth and development by protecting the seedlings from abiotic stresses through scavenging reactive oxygen species.

View Article: PubMed Central - PubMed

Affiliation: Biotechnology Research Institute, Chinese Academy of Agricultural Sciences/National Key facility for Gene Resources And Genetic Improvement, Beijing, China.

ABSTRACT
Plant ascorbate peroxidases (APXs), enzymes catalyzing the dismutation of H2O2 into H2O and O2, play an important role in reactive oxygen species homeostasis in plants. The rice genome has eight OsAPXs, but their physiological functions remain to be determined. In this report, we studied the function of OsAPX2 gene using a T-DNA knockout mutant under the treatment of drought, salt and cold stresses. The Osapx2 knockout mutant was isolated by a genetic screening of a rice T-DNA insertion library under 20% PEG-2000 treatment. Loss of function in OsAPX2 affected the growth and development of rice seedlings, resulting in semi-dwarf seedlings, yellow-green leaves, leaf lesion mimic and seed sterility. OsAPX2 expression was developmental- and spatial-regulated, and was induced by drought, salt, and cold stresses. Osapx2 mutants had lower APX activity and were sensitive to abiotic stresses; overexpression of OsAPX2 increased APX activity and enhanced stress tolerance. H2O2 and MDA levels were high in Osapx2 mutants but low in OsAPX2-OX transgenic lines relative to wild-type plants after stress treatments. Taken together, the cytosolic ascorbate peroxidase OsAPX2 plays an important role in rice growth and development by protecting the seedlings from abiotic stresses through scavenging reactive oxygen species.

Show MeSH
Related in: MedlinePlus